Question

Two identical objects, A and B, are thermally and mechanically isolated from the rest of the world. Their initial temperatures are TA > TB. Each object has heat capacity C (the same for both objects) which is independent of temperature. (a) Suppose the objects are placed in thermal contact and allowed to come to thermal equilibrium. What is their final temperature? How much entropy is created in this process? How much work is done on the outside world in this process? (b) Instead, suppose objects A (temperature TA) and B (temperature TB < TA) are used as the high and low temperature heat reservoirs of a heat engine. The engine extracts energy from object A (lowering its temperature), does work on the outside world, and dumps waste heat to object B (raising its temperature). When the temperatures of A and B are the same, the heat engine is in the same state as it started and the process is finished. Suppose this heat engine is the most efficient heat engine possible. In other words, it performs the maximum work possible. What is the final temperature of the objects? How much entropy is created in this process? How much work is done on the outside world in this process?

Answer 1

All the sub-parts are properly answered. I hope you will understand the concept clearly. Thanks for asking questions.